JPH10261835A - Semiconductor laser device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser device which is not much deteriorated in quality in forming a window structure. SOLUTION: A first p-type Alr Ga1-r As upper clad layer 4 (r=0.3) is formed on an active layer 3 constituted in a quantum well structure and ions are implanted into an area near the part which becomes the end face of a laser resonator. Then, after a window structure area 8 is formed by disordering the active layer 3 by annealing, a second p-type Alr Ga1-r As upper layer 4b (r=0.3) is formed through crystal growth and a ridge stripe-like section 15 is formed on the second upper clad layer 4b by selective etching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device and a method of manufacturing the same, and more particularly to a semiconductor laser device having a window structure at an end face and capable of high-power operation and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 3 is a partially cutaway perspective view showing the structure of a conventional semiconductor laser device. In FIG. 3, reference numeral 1 denotes an n-type (hereinafter also referred to as n-) GaAs substrate; .
N-type Al with an aluminum composition ratio x of 5 to 2 μm
_{The x} Ga _1-x As lower cladding layers 2 and 3 are made of Al _y Ga _1-y A
s (y = 0.05 to 0.15) is constructed from well layer (not _{shown) Al z Ga 1-z As} (z = 0.2~0.35) barrier layer (not shown) And a light guide layer (not shown) having the same composition as the above barrier layer having a thickness of about 35 nm, and a thickness of 10 nm therebetween.
And five barrier layers each having a thickness of about 10 nm are alternately combined, that is, three well layers and two barrier layers are laminated. 4 has a thickness of 1.5 to 2.0
μm, a p-type having an aluminum composition ratio r of 0.3 (hereinafter referred to as p
-Al _r Ga _{1 -r} As upper clad layer 10 is a p-type GaAs contact layer having a thickness of 0.5 to 1.0 μm, and the upper part of upper clad layer 4 and contact layer 10 are formed by laser resonance. The ridge stripe portion 15 has a ridge shape extending in a direction perpendicular to the container end face.
Reference numeral 16 denotes an insulating film for narrowing a current, 8 denotes a window structure region formed near the end face of the laser resonator, 20 denotes an n-side electrode, 19 denotes a p-side electrode, 35 denotes a silicon (Si) heat diffusion region, and 30 denotes a laser. This is the end face of the resonator. The size of the semiconductor laser device is such that the length in the cavity length direction is 300 to 600 μm,
The width is about 300 μm.

FIG. 4 is a process chart showing a method of manufacturing the conventional semiconductor laser device shown in FIG. 3, and shows only a portion corresponding to one side of a laser resonator end face of the semiconductor laser device. 3, the same reference numerals as those in FIG. 3 denote the same or corresponding parts, and 31 denotes a silicon nitride (SiN) film,
34 is a photoresist and 32 is a Si film.

Next, this conventional manufacturing method will be described with reference to FIG. A lower cladding layer 2, a quantum well structure layer 3, an upper cladding layer 4, and a contact layer 10 are sequentially epitaxially grown on an n-type GaAs substrate 1 in a wafer state (not shown) (FIG. 4A). Next, an SiN film 31 is formed on the surface of the contact layer 10, and the SiN film 31 is patterned to provide an opening in a region near a laser cavity end face, as shown in FIG. 4B. . This SiN film 3
The distance between 1 and the position to be the cavity end face of the semiconductor laser device is set to about 20 μm.

Subsequently, as shown in FIG.
Si so as to cover the film 31 and the contact layer 10
After the film 32 is formed, annealing is performed at a high temperature of 850 ° C. or more for 4 hours or more to convert Si from the Si film 32 into the contact layer 1.
0 to reach the lower cladding layer 2 so that S
An i heat diffusion region 35 is formed. At this time, the Si concentration of the active layer 3 in the Si thermal diffusion region 35 is 3 × 10 ¹⁸ cm ^−3.
Degree. Since the SiN film 31 is interposed between the Si film 32 and the contact layer 5 in the region below the SiN film 31, Si does not diffuse. Due to the Si diffusion accompanied by this annealing, the region near the laser resonator end face of the quantum well structure active layer 3 in the Si thermal diffusion region 35 is disordered. The region near the laser cavity end face of the disordered quantum well structure active layer 3 becomes a window structure region 8 functioning as a window structure.

[0006] Then, Si film 32, and the SiN film 31 is removed by wet etching using HF etchant or the like, as shown in FIG. 4 (d), SiO ₂ on the entire surface of the wafer by thermal CVD or the like After forming the insulating film 34 such as
The insulating film 34 is patterned by a photolithography technique and an insulating film etching technique to form a stripe having a width of about 5 to 6 μm, which extends perpendicular to the end face of the laser resonator.

Next, using the patterned insulating film 34 as a mask, the upper portions of the contact layer 10 and the upper cladding layer 4 are selectively etched to form the ridge stripe portion 15.
Is created (FIG. 4 (e)). At this time, the upper cladding layer 4
The etching rate at the predetermined height position of the upper cladding layer 4
It is also possible to provide an etching stopper layer different from that described above and to accurately control the remaining thickness of the upper cladding layer 4 by etching with an etching solution having selectivity to the material.

Subsequently, after removing the insulating film 34, an insulating film 16 is formed on the entire surface of the wafer by thermal CVD or the like, and then the insulating film 16 on the ridge stripe-shaped portion 15 is formed by photolithography and insulating film etching. To remove
The p-type contact layer 10 is exposed (FIG. 4F).

Finally, a p-side electrode 19 is formed on the wafer so as to be in contact with the contact layer 10, an n-side electrode 20 is formed on the substrate 1 side, and the laser cavity end face 30 is formed by cleavage.
Is formed to obtain a semiconductor laser device having a window structure as shown in FIG.

The operation of the conventional semiconductor laser device having the window structure shown in FIG. 3 will be described below. When a voltage is applied such that the p-side electrode 19 side is positive and the n-side electrode 20 side is negative, holes are formed in the p-GaAs contact layer from the opening of the insulating film 16 provided in the flat portion above the ridge stripe-shaped portion 15. 10, electrons are injected into the quantum well structure layer 3 through the p-AIGaAs upper cladding layer 4, and electrons are injected into the quantum well structure active layer 3 through the n-GaAs substrate 1 and the n-AlGaAs lower cladding layer 2, respectively. Structure active layer 3
In the active region, that is, in the region near the lower portion of the ridge stripe-shaped portion 15, except for the region where the window structure region 8 is formed, recombination of electrons and holes occurs, and the active region in the quantum well structure active layer 3 is formed. Stimulated emission light occurs. If the amount of injected carriers is made sufficiently high to generate light exceeding the loss of the waveguide, laser oscillation occurs.

In this conventional semiconductor laser device,
A ridge stripe-shaped portion 15 serving as a laser light waveguide is formed so as to reach the laser resonator end face 30.
For this reason, the thickness of the upper cladding layer 4 is different between the region where the ridge stripe-shaped portion 15 is formed and the region adjacent to this region, and an effective refractive index difference is generated between these regions. Light is confined and guided along the lower part of the ridge stripe-shaped portion 15 in a direction parallel to the surface of the substrate 1. Further, the active layer 3 located below the ridge stripe-shaped portion 15 is sandwiched between the lower clad layer 2 and the upper clad layer 4 having the same structure over the laser resonator end face 30, so that the laser light is Waves are confined and guided between the lower cladding layer 2 and the upper cladding layer 4 in the direction perpendicular to 1.

Next, the window structure will be described. Generally 0.
GaAs that emits laser light in the wavelength range of 75 to 1.1 μm
The maximum light output of the semiconductor laser device of the system is determined by the light output at which the end face breakdown of the semiconductor laser device occurs. This end face breakdown is a result of a decrease in the effective bandgap energy due to the non-radiative recombination of the injected carriers through the surface state in the end face area of the laser cavity of the semiconductor laser device, thereby reducing the carriers. This is because laser light is re-absorbed in the vicinity of the end face of the laser cavity, and the crystal itself constituting the semiconductor laser melts due to the heat due to the absorption, so that the function of the laser resonator cannot be achieved. Therefore, in order to realize a high light output operation, it is necessary to devise a method that does not cause end face destruction even at a higher light output. For this purpose, a structure that makes it difficult to absorb laser light in the end face region, that is, a window structure that is “transparent” to laser light is very effective. Here, the window structure is obtained by providing a region having a bandgap energy higher than that of the active region of the active layer that emits laser light in the vicinity of the end face of the laser resonator, particularly in a region including a region where light is guided. It is something that can be done.

In the conventional semiconductor laser shown in FIG. 3, since the active layer 3 has a quantum well structure, such a window structure disorders the quantum well structure 3 by Si thermal diffusion, ie, disordering. It is formed by utilizing.
FIG. 5 is a diagram showing a profile of the aluminum composition ratio near the active layer 3 for explaining the disorder.
5A shows the profile of the aluminum composition ratio of the quantum well structure active layer 3 before disordering, and FIG. 5B shows the profile of the aluminum composition ratio of the quantum well structure active layer 3 after disordering. I have. 4, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.
Reference numerals 23 and 24 denote a well layer, a barrier layer, and a light guide layer of the active layer 3, respectively. In the figure, the ordinate indicates the Al composition ratio, the abscissa indicates the height position of the lower cladding layer 2, the active layer 3, and the upper cladding layer 4 in the crystal growth direction, and Al ₂ indicates the aluminum composition of the well layer 22. Ratio, Al ₁ is the aluminum composition ratio of barrier layer 23 and light guide layer 24, Al ₃
Indicates the aluminum composition ratio of the active layer 3 after being disordered.

When silicon (Si) is diffused into the quantum well structure active layer 3 as shown in FIG.
The atoms constituting the well layer 22 and the barrier layer 23 are mixed together with the diffusion, and the diffused region is disordered as shown in FIG. 5B. As a result, the aluminum composition ratio of the disordered quantum well structure active layer 3 becomes the aluminum composition ratio Al of the barrier layer 23 and the light guide layer 24.
_The aluminum composition ratio Al ₃ is substantially equal to _1, and the effective band gap energy of the active layer 3 is substantially equal to the barrier layer 23 and the light guide layer 24.

Accordingly, in the conventional semiconductor laser shown in FIG. 3, the effective bandgap energy of the disordered region of the quantum well structure active layer 3 is reduced by the effective bandgap of the active layer 3 that is not disordered. Since the energy is larger than the energy, the disordered region of the quantum well structure active layer 3, that is, the region 3 in which Si is thermally diffused.
5, the active layer 3 is "transparent" to the laser beam.
The region near the laser resonator end face 30 of the quantum well structure active layer 3 becomes the window structure region 8.

In such a conventional semiconductor laser device having a window structure, a COD (Catastrophic optical) is compared with a semiconductor laser having no window structure due to the effect of the window structure.
Damage) level is improved, so that it can be operated stably for a long time even in a high output operation of 50 mW or more.

[0017]

However, in a conventional semiconductor laser device having a window structure, the thermal diffusion of Si is applied to the disorder of the active layer 3 in the quantum well structure. The treatment had to be performed at an annealing temperature of 850 ° C. or more for 4 hours or more to cause Si diffusion. In this case, Zn as a dopant of the p-AlGaAs upper cladding layer 4 and Si and Se as dopants of the n-AlGaAs lower cladding layer 2 are also diffused into the quantum well structure active layer 3, and are not originally contained in the window structure region. Even in an active region that emits laser light, a disorder is induced, and as a result, the active region does not function. There was a problem that good characteristics as a laser would not be exhibited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor laser device with less quality deterioration when forming a window structure, and a method of manufacturing the same.

[0019]

A semiconductor laser device according to the present invention has a first conductivity type lower cladding layer and an active layer sequentially disposed on a first conductivity type semiconductor substrate, and a ridge stripe-shaped portion thereon. A second conductivity type upper cladding layer, an insulating film formed on a region of the second conductivity type upper cladding layer other than an upper portion of the ridge stripe-shaped portion, and a direction in which the stripe of the ridge stripe-shaped portion extends. And the active layer, which is provided in the vicinity of a region located below the ridge stripe-shaped portion in the region near the laser resonator end surface of the active layer, It has a window structure region which is disordered by ion implantation and heat treatment.

In the semiconductor laser device, the ridge stripe-shaped portion of the upper cladding layer of the second conductivity type may be formed by forming the upper cladding layer of the second conductivity type on the active layer. Is formed by selectively etching the substrate.

In the above-mentioned semiconductor laser device, the second conductive type upper clad layer may be composed of a second conductive type first upper clad layer and a second conductive type second upper clad layer having a ridge stripe portion. And a second conductive type surface protection layer is provided between the first upper cladding layer and the second upper cladding layer.

Further, according to the method of manufacturing a semiconductor laser device of the present invention, the first conductive type lower clad layer, the active layer, and the second conductive type first upper clad layer are epitaxially formed on the first conductive type semiconductor substrate. A step of crystal growth, and after the above step,
Forming a photoresist film having an opening in a region near a portion where a laser cavity facet is formed on the first upper cladding layer of the second conductivity type, and using the photoresist film as a mask from above the semiconductor substrate; A step of removing the photoresist film after the ion implantation of impurities into the active layer, performing a heat treatment and disordering the active layer to form a window structure region, and after the step, the second conductive type is formed. Forming a second upper cladding layer, selectively etching an upper portion of the second upper cladding layer, and forming a region on the window structure region in a direction perpendicular to a portion where the laser resonator end face is formed; Forming a ridge stripe-shaped portion having a stripe shape extending so as to include an insulating film on a region of the second upper cladding layer of the second conductivity type other than an upper portion of the ridge stripe-shaped portion. It is obtained so as to include and.

In the method of manufacturing a semiconductor laser device, the surface of the second conductivity type may be formed on the first upper cladding layer of the second conductivity type following the epitaxial crystal growth of the first upper cladding layer of the second conductivity type. The method includes a step of continuously growing a crystal of the protective layer.

Further, in the method for manufacturing a semiconductor laser device, after the crystal growth of the surface protection layer of the second conductivity type,
The method includes a step of forming a through film made of an insulating film on the surface protective layer, and a step of selectively removing the through film after the step of forming the window structure region.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a partially cutaway perspective view showing the structure of a semiconductor laser device according to Embodiment 1 of the present invention.
In the figure, the n-type GaAs semiconductor substrate 1, 2 thickness 1.5 to 2 [mu] m, an n-type Al _x Ga _1-x As lower cladding layer of the aluminum composition ratio x of 0.3, 3 Al _y Ga _{1 -y}
As (y = 0.05 to 0.15) well layer (not shown)
And an Al _z Ga ₁ -z As (z = 0.2 to 0.35) barrier layer (not shown). A light guide layer (not shown) of the same composition, and a thickness of 10
The structure is formed by alternately combining five well layers each having a thickness of 10 nm and barrier layers each having a thickness of about 10 nm, that is, three well layers and two barrier layers. 4a has a thickness of 0.05
0.5 μm, p-type A with aluminum composition ratio r of 0.3
The l _r Ga _{1 -r} As first upper cladding layer 4 b is a p-type Al _r Ga _{1 -r} As second upper cladding layer having an aluminum composition ratio r of 0.3, and the first upper cladding layer 4 a and the second upper cladding layer 4b is constitute a p-type Al _r Ga _{1- r} As upper cladding layer 4, the thickness of the upper cladding layer 4 is 1.5~2μ
m. A p-GaAs surface protective layer is disposed between the first upper cladding layer 4a and the second upper cladding layer 4b, but is omitted here. Reference numeral 10 denotes a p-type GaAs contact layer having a thickness of 0.5 to 1.0 μm. The unit 15 is constituted. 12 is a high resistance region by proton injection, 16 is an insulating film for current narrowing,
Reference numeral 8 denotes a window structure region formed near the laser cavity end face;
0 is an n-side electrode, 19 is a p-side electrode, and 30 is a laser resonator end face. The size of the device of this semiconductor laser is
The length in the cavity length direction is 300 to 1200 μm, and the width is about 3
00 μm.

FIG. 2 is a process diagram showing a method for manufacturing the semiconductor laser device of the present invention shown in FIG. 1, and shows only a portion corresponding to one side of the laser resonator end face of the semiconductor laser device. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, 5 is a p-GaAs surface protective film for preventing the surface oxidation of the first upper cladding layer 4a, and 6 is Si nitride for protecting the crystal surface. Reference numerals 7 and 11 denote photoresists, and 14 denotes a stripe-shaped insulating film pattern.

First, a method for manufacturing a semiconductor laser device according to the first embodiment of the present invention will be described with reference to FIG. First, on an n-GaAs substrate 1 in a wafer state (not shown), an n-Al _x Ga _{1 -x} As (x = 0.3) lower cladding layer 2, a quantum well structure active layer 3, and a p-Al _r Ga _1-r As
(R = 0.3) Each layer of the first upper cladding layer 4a and the p-GaAs surface protective layer 5 is epitaxially grown sequentially. Incidentally _{p-Al r Ga 1- r As} (r = 0.3) layer thickness of the first upper cladding layer 4a is set to 0.05 to 0.5 [mu] m.
Further, after crystal growth, a through film 6 made of an insulating film is formed on the wafer surface. This film formation method is plasma CV
D, thermal CVD and the like are common. FIG. 2 is a perspective view after film formation.
(a).

Further, as shown in FIG. 2B, a photoresist 7 is applied to the surface of the through film 6 and is patterned to form a window structure region, that is, a portion to be a laser cavity end face. An opening is provided in a region including a portion serving as a laser resonator, in particular, in the vicinity region. Here, an opening is provided along the entire area of the end face of the laser resonator. At this time, the through film 6 serves to prevent contamination of the crystal surface due to the application of the photoresist 7 directly on the epitaxial crystal layer, and contamination of the crystal surface due to the stripping solution when the photoresist 7 is removed. Subsequently, using the photoresist 7 as a mask, Si ions are implanted from the upper surface of the through film 6 to the vicinity of the active layer 3. This ion implantation is preferably performed so as to stop before the active layer. Si dose at the time of Si ion implantation is 1 × 10
It should be about ¹³ to 1 × 10 ¹⁵ cm ⁻² . In addition, a photoresist 7 having a sufficient thickness is formed in a region below the photoresist 7.
Acts as a mask to prevent ion implantation into this region, so that Si ion implantation is not performed in this region. In this ion implantation, other ion-implantable impurities such as Zn (zinc) can be used in addition to Si.

Here, as shown in FIG. 2C, after the photoresist 7 is removed, a heat treatment (annealing) is performed in order to order the quantum well structure active layer 3. This is carried out because the disordering of the active layer 3 does not occur only by ion implantation, and the disordering occurs only after the Si atoms are diffused in the crystal by some kind of heat treatment. A method of annealing at the above temperature is generally used, and a disorder of about 2 hours can be sufficiently obtained. As a result, Si
The quantum well structure active layer 3 in the ion implantation region is disordered. This disordered region of the quantum well structure active layer 3 becomes a window structure region 8 functioning as a window structure.
The through film 6 functions as a protective film on the surface of the epitaxial growth layer during this annealing.

Next, after annealing, as shown in FIG. 2 (d), the through film 6 on the wafer surface is removed using an HF-based etchant, and a second crystal growth is performed to form a surface protection layer 5
_{Above, p-Al r Ga 1-} r As (r = 0.3) second upper cladding layer 4b, successively epitaxially regrown p-GaAs contact layer 10.

After the second epitaxial growth, a photoresist 11 is applied on the wafer, and the photoresist 11 is patterned, and an opening is provided on a region corresponding to the window structure region 8 as shown in FIG. _{P-Al r Ga 1-r} As (r = 0 from the wafer using the photoresist 11 as a mask.
3) perform proton implantation to a predetermined height position of the second upper cladding layer _{4b, p-Al r Ga 1} -r As (r = 0.3)
A high resistance region 12 is formed in the upper portion of the second upper cladding layer 4a and in the p-GaAs contact layer 10 by proton implantation.

Further, after removing the photoresist 11, an insulating film is formed on the contact layer 10 in the same manner as the through film 6, and is patterned by a photolithography technique and an insulating film etching technique. The stripe-shaped insulating film pattern 14 extending in the direction perpendicular to the laser cavity end face as shown in FIG.

Using the striped insulating film pattern 14 as an etching mask, the p-GaAs contact layer 1 is formed.
0 and _{p-Al r Ga 1-r} As (r = 0.3) and a second upper cladding layer _{4b, p-Al r Ga 1} -r As (r = 0.
3) By etching to a predetermined height of the second upper cladding layer 4b, a ridge stripe-shaped portion 15 is formed as shown in FIG. 2 (g). The vicinity of a region of the active layer 3 below the ridge stripe portion 15 becomes a laser waveguide.

Subsequently, the insulating film pattern 14 is selectively removed, an insulating film 16 for current confinement is formed on the wafer, and a photoresist (not shown) is applied thereon. By patterning, an opening is provided above the ridge stripe-shaped portion 15, and using this photoresist as a mask, the insulating film 16 above the ridge stripe-shaped portion 15 is removed by etching.
As shown in FIG. 2H, an insulating film 16 having a stripe-shaped opening in a flat portion above the ridge stripe-shaped portion can be formed. The insulating film 16 functions to narrow the current.

Finally, a p-side electrode 19 is formed on the wafer and an n-side electrode 20 is formed on the back surface of the substrate 1 so that an ohmic contact can be made with the contact layer 10 exposed in the opening of the insulating film 16. By forming the laser resonator end face 30 by cleavage, a semiconductor laser device having a window structure as shown in FIG. 1 is obtained.

In the semiconductor laser device according to the first embodiment, the active layer 3 near the laser resonator end face 30 is
It is disordered by a combination of Si ion implantation and annealing. For this reason, the band gap energy of the disordered region in the active layer 3 is larger than the band gap energy of the unordered region, and the disordered region of the active layer 3 is 3, the window structure region 8 which does not absorb the laser light generated particularly in the lower region of the ridge stripe-shaped portion 15 among the unordered regions.
It has become.

Here, in the first embodiment, the order of the quantum well structure active layer 3 for forming the window structure is different from the Si thermal diffusion described in the prior art, and is different from the Si ion implantation. This is performed by subsequent annealing. As a result, there is no need to perform annealing at a high temperature of 850 ° C. or more necessary for Si thermal diffusion for as long as 4 hours or more. That is, in the disorder of the active layer 3 in which the Si ion implantation and the annealing are combined according to the first embodiment, the disorder is sufficiently generated by performing the annealing at the annealing temperature of 750 to 850 ° C. for about 2 hours. . As a result, unlike the related art, a long-time heat treatment at a high temperature is not required, and the problem that the semiconductor laser device is deteriorated during the formation of the window structure region can be solved.

Also, in the Si ion implantation, the implantation profile of Si in the crystal can be controlled very accurately, and therefore, in the first embodiment, the disorder can be performed with good reproducibility and stably. A semiconductor laser device often having a window structure can be formed.

Here, in the semiconductor laser device as described in the prior art, the manufacturing method
Although it is conceivable to perform ion implantation instead of the thermal diffusion step of i, in such a case, the ion implantation is performed after the upper cladding layer and the contact layer are grown on the active layer. The distance between the surface of the layer and the contact layer is about 2 μm, and the distance from the wafer surface to the quantum well structure active layer is about 2 μm. In order to inject Si into the vicinity of the active layer, a very large acceleration voltage is obtained. A special ion implanter is required, making it difficult to manufacture easily. Even if such a device is obtained, an acceleration voltage of 1 GeV or more is necessary to implant Si into the vicinity of the active layer, and crystal defects generated during ion implantation under such a high acceleration voltage are Even with annealing, recovery is no longer possible, and when such ion implantation is performed, a serious problem occurs in the reliability of the device.

However, in the semiconductor laser device according to the first embodiment, the p-Al _r Ga ₁₋ layer having a thickness of 0.05 to 0.2 μm is formed on the quantum well structure active layer 3 in the first epitaxial crystal growth. _r As (r = 0.3) first upper cladding layer 4, p-GaAs surface protective layer 5 of 5 to 10 nm
To form only, the distance from the wafer surface to the quantum well structure active layer 3 is approximately _{p-Al r Ga 1-r} As (r =
0.3) 0.05 to the layer thickness of the first upper cladding layer 4
Since it is about 0.2 μm, a high accelerating voltage is not required, and the accelerating voltage may be about 50 to 300 keV. With such an accelerating voltage, only a defect sufficient to recover a crystal defect by annealing is generated. Also, there is no problem that the reliability of the element is impaired.

[0041] Thus, according to the first embodiment, on the quantum well structure active layer _{3 p-Al r Ga 1-} r As (r =
0.3) After forming the first upper cladding layer 4, ion implantation is performed in a region near the laser cavity end face, annealing is further performed, and the quantum well structure active layer 3 is disordered to form a window structure. After forming the region 8, p-Al _r Ga
_1-r As (r = 0.3) The second upper cladding layer 4b is crystal-grown, and the ridge stripe-shaped portion 15 is formed on the upper portion of the second upper cladding layer 4b by selective etching. It is not necessary to perform a long-time process at a high temperature when forming the region, and it is possible to provide a semiconductor laser device of excellent quality with little deterioration in quality at the time of forming the window structure and a method of manufacturing the same.

In the first embodiment, the case where the active layer has an AlGaAs quantum well structure has been described.
The present invention can be applied to an aAs / GaAs quantum well structure, an InGaAs quantum well structure, or an AlGaInP / GaInP quantum well structure. In such a case, the same effect as in the first embodiment can be obtained.

Although the first embodiment has been described using an n-type semiconductor substrate, the present invention uses a p-type semiconductor substrate and uses a p-type semiconductor layer instead of the n-type semiconductor layer. The n-type semiconductor layer may be used instead of the p-type semiconductor layer by using the n-type semiconductor layer. In such a case, the same effect as in the first embodiment can be obtained.

[0044]

As described above, according to the semiconductor laser device of the present invention, the first conductive type lower cladding layer and the active layer are sequentially arranged on the first conductive type semiconductor substrate, and the ridge stripe shape is formed on the lower clad layer and the active layer. A second conductive type upper clad layer having a portion, an insulating film formed on a region of the second conductive type upper clad layer other than an upper portion of the ridge stripe-shaped portion,
A laser cavity facet provided perpendicular to the direction in which the stripes of the ridge stripe shape extend, and a region of the active layer located under the ridge stripe shape in a region near the laser cavity facet. Since the active layer is provided with a window structure region which is formed by disordering the active layer by ion implantation of impurities and heat treatment, it is not necessary to perform a long-time process at a high temperature when forming the window structure region. In addition, there is an effect that a semiconductor laser device of excellent quality with less deterioration in quality when forming the window structure can be provided.

According to the invention, in the semiconductor laser device, the ridge stripe-shaped portion of the second conductive type upper clad layer is formed on the active layer after forming the second conductive type upper clad layer. Since the upper cladding layer is formed by selectively etching the upper portion, there is an effect that a semiconductor laser device of excellent quality with less deterioration in quality when forming the window structure can be provided.

According to the present invention, in the semiconductor laser device, the second conductive type upper cladding layer may be formed of the second conductive type.
A conductive type first upper cladding layer and a second conductive type second upper cladding layer having a ridge stripe portion,
Between the first upper cladding layer and the second upper cladding layer,
Since the surface protection layer of the second conductivity type is provided, there is an effect that it is possible to provide a semiconductor laser device of excellent quality with less deterioration in quality when forming the window structure.

According to the method of manufacturing a semiconductor laser device of the present invention, the first conductive type lower clad layer, the active layer, and the second conductive type first upper clad layer are formed on the first conductive type semiconductor substrate. Forming a photoresist film having an opening in a region near a portion where a laser cavity facet is to be formed on the second conductive type first upper cladding layer, after the step, After performing ion implantation of impurities into the active layer from above the semiconductor substrate using the photoresist film as a mask, the photoresist film is removed,
A step of forming a window structure region by performing a heat treatment and disordering the active layer, forming a second upper cladding layer of the second conductivity type after the step, and selectively covering the upper part of the second upper cladding layer. Forming a ridge stripe-shaped portion having a stripe shape extending so as to include a region on the window structure region in a direction perpendicular to a portion where the laser resonator end face is formed; and Forming an insulating film on a region of the two-conductivity-type second upper cladding layer other than the upper portion of the ridge stripe-shaped portion.
There is no need to perform long-term processing at a high temperature when forming the window structure region, and there is an effect that it is possible to provide a semiconductor laser device of excellent quality with less deterioration in quality when forming the window structure.

According to the present invention, in the method of manufacturing a semiconductor laser device, the second conductive type first upper clad layer is formed on the second conductive type first upper clad layer following the epitaxial crystal growth of the second conductive type first upper clad layer. Since the method includes the step of continuously growing a two-conductivity type surface protection layer on a crystal, there is an effect that it is possible to provide a semiconductor laser device of excellent quality with less deterioration in quality when forming the window structure.

According to the invention, in the method of manufacturing a semiconductor laser device, after the crystal growth of the surface protection layer of the second conductivity type, a through film made of an insulating film is formed on the surface protection layer. After the step and the step of forming the window structure region, a step of selectively removing the through film is provided.Therefore, a semiconductor laser device of excellent quality with less deterioration in quality at the time of forming the window structure is provided. There are effects that can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a structure of a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating a method for manufacturing the semiconductor laser device according to the first embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view showing the structure of a conventional semiconductor laser device.

FIG. 4 is a perspective view showing a method for manufacturing a conventional semiconductor laser device.

FIG. 5 is a view showing a profile of an aluminum composition ratio before and after a disorder of a quantum well structure active layer in a conventional semiconductor laser device.

[Explanation of symbols]

1 n-GaAs substrate, 2 n-Al _x Ga _1-x As
(X = 0.3) bottom cladding layer, 3 a quantum well structure active _{layer, 4 p-Al r Ga 1} -r As (r = 0.3) upper cladding _{layer, 4a p-Al r Ga 1} -r As ( r = 0.3)
The first upper cladding _{layer, 4b p-Al r Ga 1} -r As (r
= 0.3) Second upper cladding layer, 5 p-GaAs surface protective layer, 6 through film, 7 photoresist, 8 window structure region, 10 p-GaAs contact layer, 11 photoresist, 12 proton-implanted high-resistance region, 14,34
Insulating film pattern, 15 ridge stripe shape part, 1
6 insulating film, 19 p-side electrode, 20 n-side electrode, 22
A well layer in a quantum well structure active layer; a barrier layer in a quantum well structure active layer; a light guide layer in a quantum well structure active layer; a laser cavity facet; a 31 SiN film;
32 Si film, 35 Si thermal diffusion region.

Claims (6)

[Claims] A first conductive type lower cladding layer, an active layer, a second conductive type upper cladding layer having a ridge stripe-shaped portion thereon, and a second conductive type upper cladding layer disposed on the first conductive type semiconductor substrate; An insulating film formed on a region of the upper mold cladding layer other than the upper portion of the ridge stripe-shaped portion; a laser resonator end face provided perpendicular to a direction in which the stripe of the ridge stripe-shaped portion extends; A window structure provided in the vicinity of a region located below the ridge stripe-shaped portion of the active layer near the laser resonator end face, the active layer being disordered by impurity ion implantation and heat treatment. And a semiconductor laser device. 2. The semiconductor laser device according to claim 1, wherein the ridge stripe-shaped portion of the second conductive type upper clad layer is formed on the active layer after forming the second conductive type upper clad layer. A semiconductor laser device formed by selectively etching the upper part of an upper cladding layer. 3. The semiconductor laser device according to claim 1, wherein the second conductive type upper clad layer is a second conductive type first upper clad layer and a second conductive type second upper clad layer having a ridge stripe portion. A clad layer, between the first upper clad layer and the second upper clad layer,
A semiconductor laser device comprising a surface protection layer of a second conductivity type. 4. A step of epitaxially growing respective layers of a first conductivity type lower cladding layer, an active layer, and a second conductivity type first upper cladding layer on a first conductivity type semiconductor substrate; Forming a photoresist film having an opening in a region near a portion where a laser cavity facet is to be formed on the two-conductivity-type first upper cladding layer; and using the photoresist film as a mask, the active film is formed from above the semiconductor substrate. Removing the photoresist film after performing ion implantation of impurities into the layer, performing a heat treatment and disordering the active layer to form a window structure region; Forming an upper cladding layer and selectively etching an upper portion of the second upper cladding layer to include a region on the window structure region in a direction perpendicular to a portion where the laser cavity facet is formed; Stretches like Forming a rib-shaped ridge stripe-shaped portion; and forming an insulating film on a region of the second conductivity type second upper cladding layer other than the upper portion of the ridge stripe-shaped portion. Manufacturing method of a semiconductor laser device. 5. The method of manufacturing a semiconductor laser device according to claim 4, wherein the second conductive type first upper clad layer is epitaxially grown on the second conductive type first upper clad layer. A method for manufacturing a semiconductor laser device, comprising a step of continuously growing a conductive surface protective layer by crystal growth. 6. The method for manufacturing a semiconductor laser device according to claim 5, wherein after the crystal growth of the surface protective layer of the second conductivity type, a through film made of an insulating film is formed on the surface protective layer. And a step of selectively removing the through film after the step of forming the window structure region.